The present invention relates generally to the field of electrical switchboards and panel boards and more particularly to a mounting plate system used to attach or remove electrical equipment in switchboard and panelboard cabinets.
Switchgear assemblies and switchboards and panelboards are general terms which cover metal enclosures, housing switching and interrupting devices such as fuses, and circuit breakers, along with associated control, instrumentation and metering devices. Such assemblies typically include associated bus bars, interconnections and supporting structures used for the distribution of electrical power. Low voltage switchgear and switch boards operate at voltages of up to 600 volts and with continuous currents up to 5000 amps or higher. Such devices are also designed to withstand short circuit currents ranging up to 200,000 amps (3 phase RMS symmetrical).
Typical switchgear equipment is composed of a lineup of several metal and closed sections. Each section may have several circuit breakers stacked one above the other vertically in the front of the section with each breaker being enclosed in its own metal compartment. Each section has a vertical or section bus which supplies current to the breakers within the section via short horizontal branch busses. The vertical bus bars in each section are supplied with current by a horizontal main bus bar that runs through the lineup of metal and closed sections. A typical arrangement includes bus bars for each electrical phase of a multiple phase system which may include three power phases and a neutral.
During typical initial fabrication and assembly of the switchgear enclosures, it is desirable to install the rear wall of the breaker compartments from the rear (top down assembly) with the rear member of the switch gear cabinet facing upward. The vertical (section) bus is then installed top down onto the back of the rear wall of the enclosure. Subsequent assembly of the horizontal main busses and other components in the rear of the section makes removal of the rear wall of the switchgear and enclosure, from the rear, impossible without first disassembling the other structures.
Thus there is a need for a mounting plate system to enable the removal and replacement or installation of electrical equipment and more particularly the base member of electrical equipment, in the rear wall of the switchgear enclosure from the front aspect of the enclosure. There is a further need for a mounting plate system that couples to frame members of the switchgear enclosure to mount the electrical equipment in the enclosure.